Which one of the following compounds exhibits geometrical isomerism?

1.		2.
3.		4.

 The compound among the following that shows geometrical isomerism is:

1. 1-Phenyl-2-butene

2. 3-Phenyl -1-butene

3. 2-Phenyl-1-butene

4. 1,1-Diphenyl-1-propene